1. Field of the Invention
The present invention generally relates to the field of telecommunications. More particularly, the present invention relates to a telecommunications network environment having intelligent call routing and call return capabilities for routing service calls, such as emergency or poison assistance calls, to an appropriate service or control center.
2. Acronyms
The written description provided herein contains acronyms which refer to various telecommunications services, components and techniques, as well as features relating to the present invention. Although some of these acronyms are known, use of these acronyms is not strictly standardized in the art. For purposes of the written description herein, acronyms will be defined as follows:                10-Digit (10D)        Action Control Point. (ACP)        Advanced Intelligent Network (AIN)        Common Channel Signaling (CCS)        Central Office (CO)        Call Processing Record (CPR)        Data and Reporting System (DRS)        End Office (EO)        Integrated Service Control Point (ISCP)        Integrated Services Digital Network (ISDN)        Multi-Frequency (MF)        Number Plan Area (NPA)        Central Office Code (NXX)        Poison Control Answering Point (PCAP)        Poisoned Party Number (PPN)        Primary Rate Interface (PRI)        Public Service Answering Point (PSAP)        Service Creation Environment (SCE)        Service Control Point (SCP)        Service Management System (SMS)        Signaling System 7 (SS7)        Service Switching Point (SSP)        Signaling Transfer Point (STP)        Terminating Attempt Trigger (TAT)        Transaction Capabilities Applications Part (TCAP)        Transmission Control Protocol/Internet Protocol (TCP/IP)        
3. Background Information
In recent years, a number of new telephony service features have been implemented and provided by an Advanced Intelligent Network (AIN). The AIN evolved out of a need to increase the capabilities of the existing telephone network architecture and meet the growing needs of telephony customers. The AIN architecture generally comprises two networks, a data messaging network and a trunked communications network. The trunked communications network handles voice and data communications between dispersed network locations, whereas the data messaging network is provided for controlling operations of the trunked communications network.
An illustration of the basic components of an AIN network environment is shown in FIG. 1, which is provided to facilitate communication between a plurality of network locations or stations 72-86. As shown in FIG. 1, Central Offices (COs) 64-70 are provided for sending and receiving data messages from a Service Control Point (SCP) 56 via one or more Signaling Transfer Points (STPs) 51, 53 and 59. The data messages are communicated to and from the COs 64-70 and the SCP 56 along a Common Channel Signaling (CCS) network 88. Each CO 64-70 serves as a network Service Switching Point (SSP) to route telephone calls between a calling station (e.g., station 72) and a called station (e.g., station 84) through the trunked communications network 90-93.
Additional information regarding AIN and AIN-related network environments, see Berman, Roger K., and Brewster, John H., “Perspectives on the AIN Architecture,” IEEE Communications Magazine, February 1992, pp. 27-32, the disclosure of which is expressly incorporated herein by reference in its entirety.
A number of features provided by prior AIN or AIN-type intelligent networks relate to specialized call processing of incoming calls. For example, U.S. Pat. Nos. 4,611,094 and. 4,611,096, both to ASMUTH et al., disclose a system for providing custom incoming telephone call processing services to a subscriber operating at geographically diverse locations. A subscriber program stored in a central database is accessed to provide instructions to the SSPs to complete incoming calls to one of the subscriber locations in accordance with special services defined by the subscriber. The subscriber program controls the Action Control Points (ACPs) to string together the desired call processing capabilities to process each call. Specified parameters stored in the program, such as time of day, caller location, and data inputted by the caller may be utilized to determine the final destination to which each call should be completed.
U.S. Pat. No. 4,788,718, to McNABB, discloses centralized recording of call traffic information. The system provides a data gathering and recording function to the centralized database which stores the subscriber's call routing program. The subscriber's call routing program performs several functions, including presenting various announcements to callers, prompting callers for inputting information digits and collecting the resulting information digits, routing the call to a number provided by the subscriber, and performing final call dispositions other than routing to the telephone number provided by the subscriber. Processing of the call traffic information dynamically changes the subscriber's call routing program to reduce the number of blocked calls to the subscriber's telephone numbers.
U.S. Pat. No. 5,247,571, to KAY et al., discloses an Area Wide Centrex system to provide specialized calling features to stations connected to a plurality of central offices. Each of the central office switching points connects to a number of local telephone lines. The features are extended to the local telephone lines by taking the programming intelligence out of the central offices and moving it into a database located at a centralized location, such as an SCP. Service features are, controlled by the central database and are changed by reprogramming the service logic located at the central database. A variety of service features are provided including a work at home service that enables a user of a private network access from a home telephone and access authorization to increase the security of the private network.
U.S. Pat. No. 5,353,331, to EMERY et al., discloses an AIN system which connects to, and controls processing of, calls to a subscriber's wireless handset via a home base station or wireless communication network. In response to calls directed to the subscriber's wireless handset, the AIN determines where the handset is located using a central database and routes the call to that location. The incoming call can be routed directly to the handset, blocked, or routed to an alternate termination point. In response to calls from the handset, the central database provides data instructions to the landline network to extend a requested special service to the subscriber.
U.S. Pat. No. 5,592,541, to FLEISCHER, III et al., discloses an AIN network environment for forwarding incoming calls by utilizing a subscriber defined routing list. The routing list may comprise alternate telephone numbers to which calls placed to the subscriber's number(s) will be routed. The routing lists may be defined for forwarding incoming calls to other numbers for either all of the numbers or for selected groups of one or more numbers. Incoming calls may also be routed according to the time-of-day, day-of-week, percentage allocation, specific date, originating location of calling party, or calling party selection.
While prior AIN or AIN-type intelligent network applications have provided various call forwarding and routing features as indicated above, such prior attempts have not provided intelligent call routing capabilities for routing service calls to predetermined service or control centers. For instance, with the development of emergency and poison assistance control centers by state and local governments, there is an increasing need to provide intelligent call routing capabilities to facilitate the handling and routing of emergency or poison assistance calls, so that calls may be directed to the most appropriate or nearest control center. It would be desirable, for example, to provide an intelligent network environment that is capable of routing calls based on the location of the calling party and the availability of designated service or control centers. Prior attempts have also not provided system flexibility in terms of providing various routing and/or call return options that may be combined with routing based on the location of the calling party.
Such features would be highly desirable for service or control centers that provide assistance to individuals or members of the general public who dial a single publicized telephone number. With intelligent routing capabilities, calls could be automatically directed to the most appropriate control or service center, without requiring additional information or assistance from the calling party. Further, with flexible routing options, calls could be routed away from under-staffed or closed centers (e.g., based on the time-of-day, day-of-week, percentage allocation, etc.) so that reliable service or assistance may be provided to end users.